Drafting table with single pedal control of both vertical movement and tilting



DRAFTING TABLE, WITH SINGLE PEDAL CONTROL OF E J. P. E. KOOI Jan. 23,1968 VERTICAL MOVEMENT AND TILTING Filed April l2,- 1966 2 Sheets-Sheet1 INVENTOR- JOHAN F! E. KOOI BY M lyn4 PATENT AGENTS J. P. E. KOOI3,364,881 DRAFTING TABLE, WITH SINGLE PEDAL CONTROL OF BOTH Jan. 23,1968 VERTICAL MOVEMENT AND TILTING Filed April 12, 1966 2 Sheets-Sheet 2INVENTOR.

PATENT AGENTS United States Patent Oflfice 3,364,881 DRAFTING TABLE WITHSINGLE PEDAL CON- TROL OF BOTH VERTICAL MOVEMENT AND TILTING Johan P. E.Kooi, Ancaster, Ontario, Canada, assignor to Keuftel & Esser of CanadaLimited, Montreal, Quebec, Canada Filed Apr. 12, 1966, Ser. No. 542,16213 Claims. (Cl. 108-10) This invention is concerned with improvements inor relating to drafting tables, and especially to such tables which areadjustable so that an operator can change at will the inclination and/or the height of the table.

A number of problems are encountered in the construction of anadjustable drafting table. It is usually desired that both theinclination and the height of the table be adjustable individually orsimultaneously, preferably without one adjustment affecting the other,and yet the table top must be held securely at all times in the positionto which it was last adjusted. The table top is usually comparativelyheavy, and its weight must therefore be counter-balanced in some way. Ithas been known to use springs as counterbalances, but difiiculty isoften experienced since the loading of the springs may vary with theposition of the table, and means must be provided to adjust the springloading to accommodate different types of top, and ditferent additionalequipment that may be fastened to the top. In addition, the draftingtable should have the usual commercial requisites of attractive externalappearance, robust and trouble-free construction, and low initial cost.

It is an object of the present invention to provide a new adjustabledrafting table.

It is another object to provide a new adjustable drafting table thatpermits ready adjustment of the inclination and/ or height of the tabletop by operation of a single control.

In accordance with the present invention there is provided a draftingtable comprising a table body, a leg assembly mounted by said body forgenerally vertical movement with respect thereto, a table top mounted bysaid leg assembly for corresponding generally vertical movement withrespect to the body and also for tilting movement with respect to thebody about a generally horizontal axis, the leg assembly comprising afirst leg member pivotally connected to the table top about the saidhorizontal axis, a second leg member movable relative to the first legmember and connected to the table top at a point spaced from saidhorizontal axis, and retaining means mounted by the table body andcomprising first retaining means releasably retaining the leg assemblyagainst said movement with respect to the table body and secondretaining means releasably retaining the two leg members against thesaid relative movement for releasably retaining the table against thesaid tilting movement.

A drafting table which is a particular preferred embodiment of theinvention will now be described, by way of example, with reference tothe accompanying drawings wherein:

FIGURE 1 is a general perspective view of a drafting table, with partsthereof shown broken away as necessary for the opearting mechanism to beseen,

FIGURE 2 is a cross-section of a detail, taken on the line 22 of FIGURE1,

FIGURE 3 is a view of a specific part of the table, namely a support legthereof, with part broken away to show its interior,

FIGURE 4 is a view similar to FIGURE 1, of the lower part of the table,to show the said first and second releasable retaining means,

3,354,881 Patented Jan. 23, 1968 FIGURE 5 is a section taken along theline 55 of FIGURE 4, and

FIGURE 6 is a section taken along the line 66 of FIGURE 5.

In general, the new drafting table comprises a table body 19 mounted ontwo spaced elongated parallel feet 11, the body it supporting a tabletop 12 by means of an intervening leg support structure, which comprisestwo spaced leg assemblies 13. The arrangement is such that the table topcan be raised or lowered relative to the body (as indicated by thearrows 14 in FIGURE 1), and can be also tilted at different inclinationsrelative thereto (as indicated by the arrows 15 in FIGURES l and 3).

The table top 12 can be of any conventional construction, and is rigidlysecured to two spaced parallel supporting members 16 of channel form,the mouths of the channels opening downwards. Each member 16 ispivotally connected by a pivot pin 17 about a generally horizontal pivotaxis, to a respective downwardly-extending hollow main leg member 18 ofthe associated assembly 13. Each member 16 is also pivotally connected,by a pivot pin 19 about a corresponding horizontal pivot axis generallyparallel to the pivot axis of the pin 17, to a respective subsidiary legmember 29 which is capable of telescoping motion relative to and Withinthe associated main leg member 18. Each main leg member has a majorstraight portion thereof generally rectangular transverse cross section,with the two sides that constitute the shorter sides of the rectanglebifurcated by respective longitudinal slots 21, so that the furcationsconstituting the said two longer sides are capable of some freedom ofmovement towards and away from one another in directions parallel to thesaid shorter sides. A flat plate 22 extends between the longer sidesparallel thereto and approximately midway between them, being mountedfor limited sideways floating movement on three spaced pins 23 (FIGURES2 and 3).

Each subsidiary leg member 21 is also bifurcated, comprising two spacedsolid bars which extend on either side of the plate 22, each bar beinggenerally in easy rubbing sliding contact with the plate and with theimmediately adjacent longer side, A pin 24 extends between the two bars,engages the rear edge of the plate 22, and is constrained to move in thegap between the said rear edge and the immediately adjacent shorter edgeof the member 18.

The tilting motion of the table top is specifically illustrated inFIGURE 3, and it will be seen that the pivot pin 17 may be regarded asfixed, while the pin 19 moves in an are on the centre provided by thepin 17 (as indicated by the arrow 15), The pin 24 constrains the bottomend of the subsidiary leg to follow a straight line pa th, while thehollow main leg 18 is sulficiently long or deep in its transversecross-section to accommodate the transverse motion of the subsidiary legupon the said relative telescoping motion.

Each leg assembly 13 is individually mounted for free vertical movementin the table body 10 by means of two pairs of grooved rollers 25, thepairs being spaced vertically from one another, and the two rollers ofeach pair engaging respective shorter sides of the main leg member. Therollers are mounted by conventional means in two spaced parallel channelmembers 26, disposed with their mouths facing one another, the members26 in turn being securely mounted in any suitable manner in the frame 27of the table body. In this particular embodiment the frame 27 comprisesrigid members connected in a boxlike structure, to which decorativepanels such as 28 are fastened, but in other embodiments otherarrangements may be employed, as will be apparent to those skilled inthe art.

A bracket 29 is fastened to the lower end of each main leg member andhas connected thereto one end of a respective chain 30. Each chainpasses over a respective sprocket 31 that is fixed to and rotatable witha shaft 32 rotatably mounted in bearings carried by a plate 33 fastenedto the members 26. The other end of each chain is fastened toarespective end of a counterweight 34. This counterweight is mounted forfree vertical movement in the table body by two pairs of rollers 35,each pair being mounted at a different end of the counterweight, andengaging one web of an L-section member 36 fastened to the adjacentmember 26. It will be seen that the members 26 and 36 are somewhatinclined to the vertical, so that the rollers 25 are held in engagementwith the said web by gravity. As the two leg assemblies move upward, thecounterweight 34 moves downward, and vice versa, the chains 30, thesprockets 31, and the common axle 32 constituting a positive connectionbetween the assemblies which causes them to move together and ensuresthat the table pivot axis will remain horizontal for all positions ofthe table.

In this embodiment the counterweight 34 is in the form of an open-toppedbox into which Weights of various types may be loaded, e.g. metal orcement pieces, or even sand, until the desired counter balance with thetable top and leg assemblies is achieved. The effective weight of thecounterbalance remains constant for all positions of the table, and itseffective weight can be adjusted with precision at any time. if theweight of the table top is changed, e.g. by substituting a top of adifferent size, or adding a drafting instrument, the counterbalanceweight can quickly and simply be changed correspondingly.

A counterbalance problem is also encountered in the tilting of the tabletop, in that sometimes a bare top is used, while at other times arelatively heavy drafting machine is clamped to the top edge thereof andunbalances the top, causing it to try to tilt as soon as the clamp meansare released. To provide the necessary balance a channel member 37 isscrewed to the under side of the top, as by screws 38, to provide anopen-ended passage into which a counterbalance weight 39 of suitablesize can be slid and retained therein by set screws such as 49. It willbe understood that the appropriate Weight 3? is first chosen, and thenthe counterweight 34 adjusted for the total weight of the table top etc.A portion 41 of the member 37 extends beneath the lower edge of thetable and provides a pencil trough.

Means for releasably retaining the table top at any in clination andheight to which it has been set by an operator will now be described. Arelatively massive fixed clamp bar 42 is mounted at each side of thetable body at the top thereof, between the two channel members 26. Twospaced parallel pins 43 extend from the fixed bar 42 and a movable clampbar 44 is mounted for free sliding movement on the pins 43, the bars 42and 44 and the pins 43 constituting a clamp assembly which embraces thepart of the leg assembly at which the two leg members are bifurcated andare telescoped together. If a suitable releasable clam ing force isapplied to the movable bar 44 then the main leg members 13, the two barsof the subsidiary leg member 20 and the plate 22 are clamped tightly incontact with one another, preventing simultaneously the said verticaland tilting movements of the table. It will be seen that the plate 22has a function in addition to guiding the pin 24 of providing twoadditional surfaces for frictional clamping engagement with the bars ofthe leg member Ztl.

In this embodiment the means for providing the releasable clamping forcecomprises two push rods 45, mounted with their longitudinal axescoextensive in respective cross bars 46, one end of each rod beingconnected to a'respective movable bar 44, while the two immediatelyadjacent ends a e engaged with a wedge cam 47, Referring especially toFIGURE 6, the wedge cam 47 comprises a wedge member 48 mounted in aU-shaped member 49 and clamped rigidly therein by a pushrod which has ascrew-threaded portion passing through the base of the U-member 4% andthe cam member 48. The position of the wedge cam longitudinally of therod 50 can be adjusted by means of two nuts 51, while the length of thepush-rods can be adjusted by nuts 52 thereof. The other end of the rodStl'is connected by a pivot pin 53 to a lever 54, which is in turnpivoted by a pin 56 to uprights 57 of the body 10. The lever 54 isbiased or urged in the upward direction (as seen in the drawings) by aplurality of tension springs 58 (only two shown) connected between amovable transverse bar 59 of the lever 54 and a fixed transverse bar 6%mounted in the uprights.

The springs 58 urge the rod upward in the direo tion of the arrow 61 inFIGURE 6, causing the wedge cam 47 to urge the rods 45 outward in thedirection of the arrows 62, so that the required clamping force isapplied to the a bars 44. An operator wishing'to change the heightand/or the inclination of the table top steps on a foot pedal 63 of thelever 54 and depresses the lever in the direction of the arrow 64against the action of the springs 58, thereby moving the rod 51}downwards in the direction of the arrow 65 and permitting the rods 45 tomove in the directions of the arrows 66. The operator at this time hasboth hands free to adjust the table, which is virtually weightlessbecause of the action of the counterweight 34, and has virtually notendency to tilt about its pivot axis because of the action of thecounterweight 39; when the table position is adjusted to hissatisfaction, the

operator merely releases the foot pedal 63, whereupon the table isclamped securely in its new position.

Various modifications are possible. For example, al though in thisembodiment the two members of each leg assembly telescope one within theother, it is contemplated that in other embodiments they will simplymove verti cally relative to one another side by side. Other forms ofretaining means can be provided, such as movable retaining pins whichenter holes in the leg members, but such means do not provide such awide range of adjust ment as those particularly illustrated. Other formsof clamping means may also be provided, for example, pivoted pads whichare individually spring engaged with the leg assemblies, and arereleased from a single operators control by means of connecting flexiblecables. Other em bodiments within the scope of the appended claims willbe apparent to those skilled in the art.

What we claim is:

1. A drafting table comprising a table body, a leg as sembly mounted bythe body for generally vertical movement with respect thereto, a tabletop mounted by said leg assembly for corresponding generally verticalmovement .with respect to the body and also for tilting movement withrespect to the body about a generally horizontal axis, the leg assemblycomprising a first leg member pivotally connected to the table top aboutthe said horizontal axis, a second leg member movable relative to thefirst leg member and connected to the table top at a point spaced fromsaid horizontal axis, and retaining means mounted by the table body andcomprising first retaining means releasably retaining the leg assemblyagainst said movement with respect to the table body and secondretaining means releasably retaining the two leg membersagainst the saidrelative movement for releasably retaining the table against the saidtilting movement.

2. A drafting table as claimed in claim 1, wherein the said first andsecond leg members are telescoped one within the other.

3. A drafting table as claimed in claim 1, wherein the said first andsecond releasable retaining means comprise a single clamp means mountedby the table body, releasably clamping each leg assembly to the tablebody against the said vertical movement with respect thereto, andreleasably clamping the said first and second leg members of each legassembly together to retain them against the said relative movementtherebetween.

4. A drafting table as claimed in claim 1, and comprising two spaced legassemblies, and means connecting the said leg assemblies forsimultaneous vertical movement.

5. A drafting table as claimed in claim 1, wherein the second leg memberis movable vertically relative to the first leg member and is pivotallyconnected to the table top about a second axis spaced from and parallelto the first axis, said second releasable retaining means comprisingmeans retaining the two members against the said vertical movement.

6. A drafting table as claimed in claim 1, and comprising means at leastadjacent the lower edge of the table top for the reception and retentionof a counterbalance weight for balancing the table top in said tiltingmovement thereof. Y 7. A drafting table as claimed in claim 5, whereinthe said first and second leg members are telescoped one within theother for the said vertical relative movement.

8. A drafting table as claimed in claim 5, wherein the second releasableretaining means comprise clamping means which clamp the said first andsecond leg members together to retain them against the said relativemovement.

9. A drafting table as claimed in claim 5, wherein the said first andsecond releasable retaining means comprise a single clamp means mountedby the table body, releasably clamping each leg assembly to the tablebody against the said vertical movement with respect thereto, andreleasably clamping said first and second leg members of each legassembly together to retain them against the said relative verticalmovement therebetween.

10, A drafting table as claimed in claim 3, wherein each leg assemblycomprises a hollow first leg member bifurcated along its length toprovide two parts thereof movable toward and away from one another, asecond leg member slidably telescoping Within the first leg member, andwherein the said clamping releasable retaining means comprise twoclamping members mounted by the table body, each for clamping engagementwith a corresponding movable part of the first leg member, and means forurging the two clamping members toward one another.

11. A drafting table as claimed in claim 10, wherein the said second legmember is bifurcated along its length and there is provided a platemember rigidly connected 6 with the first leg member, disposed betweenthe bifurcations of the second leg member and against which the saidfurcations are clamped.

12. A drafting table as claimed in claim 10, wherein the said urgingmeans comprise a horizontally movable push-rod engaging one of theclamping members, a wedge cam engaging the said push-rod, a verticallymovable pushrod for moving the wedge cam, spring means urging thevertically movable push-rod to apply clamping force to thelast-mentioned clamping member, and a foot-operated pedal for moving thevertically movable push-rod against the urge of the spring means.

13. A drafting table comprising a table body, a leg assembly mounted bysaid body for generally vertical movement with respect thereto, firstmeans for releasably retaining the leg assembly against said verticalmovement With respect to the table body, a table top mounted by said legassembly for tilting movement with respect to the body about a generallyhorizontal axis, the leg assembly comprising a first leg memberpivotally connected to the table top about the said horizontal axis, asecond leg member movable relative to the first leg member and pivotallyconnected to the table top about a second axis spaced from and parallelto the said horizontal axis, and second means for retaining the twomembers against the said vertical movement to releasably retain thetable top against the said tilting movement.

References Iited UNITED STATES PATENTS 928,185 7/1909 Dey 108--l471,859,456 5/1932 Nestler 1082 1,956,546 4/1934 Froelich 108-2 2,646,3227/1953 Laxo 108l47 2,710,780 6/1955 Lawes 1082 2,775,497 12/1956 Alvarez108146 2,860,938 11/1958 Marti 1082 2,924,299 2/ 1960 Kanzelberger etal. 188-67 3,140,559 7/1964 Grow et a1. 1086 3,213,809 10/1965 Kritske108-146 BOBBY R. GAY, Primary Examiner. GLENN O. FINCH, AssistantExaminer.

1. A DRAFTING TABLE COMPRISING A TABLE BODY, A LEG ASSEMBLY MOUNTED BYTHE BODY FOR GENERALLY VERTICAL MOVEMENT WITH RESPECT THERETO, A TABLETOP MOUNTED BY SAID LEG ASSEMBLY FOR CORRESPONDING GENERALLY VERTICALMOVEMENT WITH RESPECT TO THE BODY AND ALSO FOR TILTING MOVEMENT WITHRESPECT TO THE BODY ABOUT A GENERALLY HORIZONTAL AXIS, THE LEG ASSEMBLYCOMPRISING A FIRST LEG MEMBER PIVOTALLY CONNECTED TO THE TABLE TOP ABOUTTHE SAID HORIZONTAL AXIS, A SECOND LEG MEMBER MOVABLE RELATIVE TO THEFIRST LEG MEMBER AND CONNECTED TO THE TABLE TOP AT A POINT SPACED FROMSAID HORIZONTAL AXIS, AND RETAINING MEANS MOUNTED BY THE TABLE BODY ANDCOMPRISING FIRST RETAINING MEANS RELEASABLY RETAINING THE LEG ASSEMBLYAGAINST SAID MOVEMENT WITH RESPECT TO THE TABLE BODY AND SECONDRETAINING MEANS RELEASABLY RETAINING THE TWO LEG MEMBERS AGAINST THESAID RELATIVE MOVEMENT FOR RELEASABLY RETAINING THE TABLE AGAINST THESAID TILTING MOVEMENT.